The utility model discloses an anti-lost bottle cap structure which is suitable for being combined with a bottle mouth of a bottle. The anti-lost bottle cap structure comprises a ring, a cap, a connecting part and a stop part, wherein the ring is combined with the root of the bottle mouth in a sleeved mode; the ring is provided with a receding groove; the cap is combined with the bottle mouth in a sleeved mode; the connecting part is arranged between the ring and the cap and used for connecting the ring with the cap; the stop part is formed by extending from the periphery of the open end in the direction of the ring and extends to the receding groove. Through the unique design of the bottle cap structure, after the cap is unscrewed from the bottle mouth, the tail end of the stop part abuts against the outer side face of the bottle mouth, the cap is limited from rebounding, the bottle mouth is kept at the open state, a user operates the anti-lost bottle cap structure easily, and the bottle cap structure is prevented from falling off or being lost.